Just had a similar situation with one of the sensors on our 507 system. I replaced the battery and it lasted a week before acting up again. I sent an e mail to the customer service department and asked what the proper procedure would be to get it corrected. They responded back to send it in. If it was under warranty they would repair or replace it NC. If it was out of warranty they would notify me what the repair or replacement would cost.
I sent the sensor to them Priority mail. It was repaired and returned a week later. There was no paperwork with it. Just a sensor in a bubble envelope. They haven't sent me a bill so at this point I'm assuming it was covered under warranty.
Hikerdogs
2013 Winnebago Adventurer